C-13 NMR-STUDIES OF GLYCININ AND BETA-CONGLYCININ AT NEUTRAL PH

Carbon-13 NMR spectra have been obtained at 4.7 T for soy β-conglycinin and glycinin in pH 7.0 solutions containing 35 mM phosphate and 0.4 M NaCl. Peak assignments for amino acids in both proteins and for the carbohydrate side chain of β-conglycinin were based on published compositions and chemical shifts and the results of J-modulated double-spin-echo experiments. Structural differences between glycinin and β-conglycinin included (a) differences in the apparent areas of spectral envelopes for aliphatic, α-carbon, and carboxyl groups and (b) bandwidth differences in peaks for glutamine and glutamate, (c) differences in backbone and side-chain flexibility, and (d) appearance of the carbohydrate moiety of β-conglycinin. Structural similarities included (1) proline in the trans conformation and (2) a single peak for the guanidino carbon of arginine. © 1990, American Chemical Society. All rights reserved.